The present invention refers to a friction cone gearing for transmitting power from a driving unit to a driven unit, and in particular to a friction cone gearing of a type having two bevel wheels mounted on parallel shafts for rotation in opposite directions and defined by a same taper angle, and a friction ring clamped between the bevel wheels and encircling one of the bevel wheels, with the friction ring being guided along the generatrix of both bevel wheels.
A friction cone gearing of this type is known from British Pat. No. 298,676, which describes the provision of a guide member held parallel to the shafts of the bevel wheels on a guide shaft for direct the friction ring along the bevel wheels, effecting a stepless adjustment of the transmission ratio of the friction cone gearing. The bevel wheels are supported in two opposite anti-friction bearings, with lubricant reducing friction in the area of the bearings of the bevel wheels and between the bevel wheels and the friction ring.
In order to effect a good power transmission from one bevel wheel via the friction ring to the other bevel wheel, various surface characteristics of the bevel wheels were proposed. In particular, rubber-like surfaces have proven especially effective in order to realize a good power transmission. These types of surfaces suffer, however, shortcomings as far as longevity is concerned as a result of their susceptibility to wear.